Shots the doctor gives you

I've only gotten 2 shots in my butt over my lifetime but they hurt! It was worse having my younger brother watch me bend over and have a needle pushed in my butt. Ouch!

I once self-spanking on the day I had to get a shot which I forgot about. The cord I used left some lines, which were still visible when I lowered my pants (I'm male and the shot was given by a female). I lowered pants only a bit, but she said she can't give a shot like this and move them down herself to even greater shame. She pretended not to see the lines, but I was very embarrassed.